1. Field of the Invention
The present invention relates generally to a pipe element for use in a heat exchanger, or more particularly to an element to be incorporated in a so-called heat pipe for use in a heat exchanger.
The heat-pipe structure used in a heat exchanger, is today attracting attention as an efficient means of heat exchanging. It is simple in construction and is particularly effective in recovering waste heat in various industrial fields. The common structure of the prior art heat pipe is such that there is provided a capillary element or a so-called wick element with a working fluid sealed therewithin, and this wick element is encased in a container which is kept in a vacuum.
2. Description of the Prior Art
A typical example of structures for such capillary elements or wick elements for a sealed container of tubular shape which serves as a heat pipe for use in a heat exchanger, is one in which a layer or layers of sintered metal is provided around the inner circumference of the tubular container, or one in which a screen or porous material is lined in the inner circumference of the container. There is also a structure in which a screen structure is provided over the inner circumference formed with a plurality grooves.
These conventional structures, however, accompany some unavoidable drawbacks. A substantial flow resistance can, for instance, be caused on the heat exchanging medium due to the use of the screen and/or sintered metal structure within the outer pipe. There is also a possibility of the wick or the capillary element being dogged up with impurities passing through the capillary spaces. Also, as disclosed in the Japanese Patent Laid-Open Applications Nos. 35151/1976 and 82445/1976, there are undulations or corrugations formed in the inner circumference of such pipe structure or porous element incorporated in the narrow gap defined with the inner circumferential surface of the pipe structure.
These conventional structures naturally require additional labor, and moreover, the relatively weak capillary effect, makes it difficult to expect fully reliable wick or capillary functions. Furthermore, the formation of vacuum within the tubular container is extremely difficult.
An improvement of this conventional heat pipe structure by using the invented method would solve all the problems mentioned above. This invention is primarily aimed at improving the conventional heat pipe structures.